An installation for smelting metal parts by casting in sand blocks generally comprises a vertical blow molding machine in which the blocks are obtained and a casting installation in which it pours the molten metal in the blocks. Once the molten metal has cooled and the molded part has solidified, said part is released from the mold by means of breaking the sand mold which falls apart. The blocks produced in the molding machine move forward to the casting station and then to the mold release area by means of a series of conveyors.
At the outlet of the molding machine there is arranged a mold or block conveyor, such as an automatic mold conveyor (“AMC”) or a precision mold conveyor (“PMC”) for example, conveying the blocks to the next work station, such as a synchronized belt conveyor (“SBC”) for example. The mold or block conveyor must be synchronized with the exit of the blocks formed in the molding machine so that the blocks are arranged in a precise row and so that they can furthermore be delivered to the next work station.
A conventional mold or block conveyor comprises a block inlet and a block outlet and a supporting grille mounted in a frame and in which there is supported a plurality of blocks in positions that are moved forward successively, as well as a clamping mechanism which can move longitudinally with respect to the supporting grille. The clamping mechanism comprises respective longitudinal clamps arranged on opposite sides along the supporting grille. Each of the clamps is also transversely movable by a plurality of actuators moving the clamps transversely between a clamping position in which they can hold the blocks against one another, and a release position in which they are not in contact with the blocks. A reciprocating mechanism is connected to the clamping mechanism to move the clamps forward when they are in their clamping position and to move the clamps backward when they are in their release position.
In conventional mold or block conveyors, the reciprocating mechanism is hydraulic and comprises a hydraulic cylinder acting on a transverse rocker arm rocking on a fixed support. The rocker arm is connected to respective connecting rods which are in turn connected to the respective clamping mechanisms. The retraction/extension movement of the hydraulic cylinder generates movements that are transmitted to the clamping mechanism in the form of reciprocating linear movements. The reciprocating mechanism is usually arranged at the outlet of the block conveyor to reduce the risk of damage to the blocks (filled with molten metal) and to avoid synchronization problems that can lead to the columns of blocks that are pushed out of the molding machine opening up.
Although conventional conveyors provide reasonable conveyance synchronization, they have drawbacks relating to the actuation and maintenance of the hydraulic cylinder and due to the fact that the rocker arm is a transverse element exposed to sand falling onto out of the blocks and preventing the arrangement of sand cleaning elements, such as a sand extraction band for example, extending below the entire conveyor for the automatic cleaning of the low area of the conveyor.